plymouthcranbrook Posted October 28, 2014 Report Share Posted October 28, 2014 (edited) so maybe you can help me with a moderate problem with my 1952 Cranbrook. I had mentioned earlier that I was changing my intake /exhaust manifold due to a vacuum leak bad enough that the car would not idle anymore. I changed the gasket(all but the exhaust/intake one) and the problem seemed to be much better. However now the car is what I will call cold blooded to lack a better term. For the first 5 or 6 miles the car seems to be running lean. By that I mean stumbling and sputtering under moderate acceleration. After that the car begins running quite well. So far I have adjusted the carb(which was rebuilt about 300 miles ago). I watched the choke open and although it appears to be a little slow on starting to opening it does go slowly and does open all the way. Plugs are nicely tan in color. Points are at 20 thousand and plugs at 35 thousand. Cap and rotor are almost new as is the coil and condenser. Wires and plugs new as well. I did add a fuel filter to the line between the pump and carb. And although this may or may not be connected, I noticed that after each moderate drive(40-50 miles) I find that I can tighten the manifold nuts about a 1/4 turn each and also the carb to manifold nuts also seem to work loose( I did not locktight them, should I have?). They do have lock washers. I did not use any sealer on the manifold to block gasket as I have never needed to to so before. I was not able to tighten the back lower exhaust manifold nut or the lower center one on the intake as I can only access them from below. I will be tightening them when I jack it up to change oil later this week. I am wondering if anyone else has had these nuts work loose like this. I had planned to retighten them when I put the car away for winter next week anyway. I do plan to check the timing and vacuum later this week as well. Although because the car runs so well after a long warm up I would be surprised to find anything wrong there. So as always any help is greatly appreciated. Thanks in advance. Edited October 28, 2014 by plymouthcranbrook Quote Link to comment Share on other sites More sharing options...
Roadkingcoupe Posted October 28, 2014 Report Share Posted October 28, 2014 heat riser? spring? any chance it was damaged or broke? Quote Link to comment Share on other sites More sharing options...
plymouthcranbrook Posted October 28, 2014 Author Report Share Posted October 28, 2014 If moves freely and seems to have a resistance to moving it by hand. 1968 was the last year I fooled with flatheads before getting this one and I really don't remember ever even having a problem like this. How much resistance should it feel like. Lots, or little or? Quote Link to comment Share on other sites More sharing options...
Roadkingcoupe Posted October 28, 2014 Report Share Posted October 28, 2014 When the motor is cold the manifold heat riser re-directs hot exhaust once the motor heats up the bi-metal spring will expand and the counter weight will move the "flap" inside the manifold approximately 90 degrees If the counter weight (and therefor) the flap doesn't move then it isn't working If the spring isnt working then the engine will run "rough" until the motor heats up to operating temps. Quote Link to comment Share on other sites More sharing options...
plymouthcranbrook Posted October 29, 2014 Author Report Share Posted October 29, 2014 As the engine heats up and I blip the throttle the heat riser does move freely. Quote Link to comment Share on other sites More sharing options...
Jeff Balazs Posted October 30, 2014 Report Share Posted October 30, 2014 I don't think it is all that unusual to have to re torque all the manifold bolts 2 or 3 times after you have had them off. If you think about it it makes perfect sense. You have put it all together with new gaskets and tightened it up while at ambient temperatures. When you run the it and it comes up to operating temperature all that cast iron expands. Gaskets compress....fasteners stretch and it all needs to be re torqued. After you have done this 2 or 3 times it should stabilize and only need checking once and a while. I am interested to hear what others have to say about the way your car runs before it gets warmed up. I have a feeling that is a carburetor setting that is not quite right. I have had similar issues with the way my truck runs. Once it is warmed up all is good. But it is a cold blooded son of a gun for at least the first 10 minutes. Jeff Quote Link to comment Share on other sites More sharing options...
plymouthcranbrook Posted October 30, 2014 Author Report Share Posted October 30, 2014 (edited) I don't think it is all that unusual to have to re torque all the manifold bolts 2 or 3 times after you have had them off. If you think about it it makes perfect sense. You have put it all together with new gaskets and tightened it up while at ambient temperatures. When you run the it and it comes up to operating temperature all that cast iron expands. Gaskets compress....fasteners stretch and it all needs to be re torqued. After you have done this 2 or 3 times it should stabilize and only need checking once and a while. I am interested to hear what others have to say about the way your car runs before it gets warmed up. I have a feeling that is a carburetor setting that is not quite right. I have had similar issues with the way my truck runs. Once it is warmed up all is good. But it is a cold blooded son of a gun for at least the first 10 minutes. Jeff Thank you. I have replace various gaskets over the years and really cannot remember having to tighten so much. Appreciate the input. Makes me feel better. hopefully tomorrow I am going to attach the vacuum gauge and adjust to best vacuum, unless the gauge shows something different. I no longer have a test tach so vacuum is the best I can do for now. Edited October 30, 2014 by plymouthcranbrook Quote Link to comment Share on other sites More sharing options...
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